LOS ANGELES — During the first timeout, a few minutes into Wednesday’s game between the Los Angeles Clippers and the Oklahoma City Thunder at Staples Center here, Steven A. Ballmer looked up from his courtside seat at the fans still filtering in. “There are still some empty seats,” he said.

Ballmer, the former Microsoft chief executive who bought the Clippers two and a half years ago from Donald and Shelly Sterling, was not concerned that the seats would remain empty. The game was sold out, just like every Clippers game since Feb. 2, 2011. Rather, his issue was the Los Angeles traffic, the unavoidable pregame snarl that kept too many fans from getting to their seats on time. Even before the tip-off, he wanted the arena full of fans who were as enthusiastic about the Clippers as he was.

“I like the noise,” he said. “I want the excitement. I want the fans to be into the game, to be part of it.”

Ballmer, who spent more than three decades at Microsoft and is worth an estimated $24 billion, paid the Sterlings a staggering $2 billion for the team — more than double what anyone else has ever paid for a professional basketball team. Many people thought he had overpaid for a franchise that had always played second fiddle to the Lakers, and remains at least a notch below the likes of the Golden State Warriors and the San Antonio Spurs. But for Ballmer, it’s been worth every penny.

In Donald Sterling, the Clippers had an owner who didn’t disguise the fact that he was more interested in profits than in wins. He made money by running the team on the cheap, refusing to re-sign young stars as they became eligible for free agency, for instance. In the last few years of his tenure, however, he had signed forward Blake Griffin and point guard Chris Paul to maximum contracts, and the team had become both exciting and good, if not yet great.

“Even when things were going well, you just knew something horrendous would happen to mess it up,” said Ralph Lawler, the longtime voice of the Clippers, speaking of the Sterling era. With Ballmer in charge, he added, “that cloud has lifted.”

The Clippers are still built around players who joined the team under Sterling. The main thing Ballmer has done on the basketball side is help persuade the Clippers’ third star, center DeAndre Jordan, to re-sign with the team — for the maximum salary — instead of going to the Dallas Mavericks.

More important for the long term, Ballmer has changed the team’s culture, re-energizing the front office, focusing on making Clippers games more fun for fans — and creating an atmosphere that gives players and fans alike hope that a championship will one day soon be within their grasp.

At the news conference after he bought the team, he began screaming — screaming, the way he famously used to do at Microsoft events — in his excitement over being the Clippers’ new owner. “He is a fan,” Paul said. “And his energy is contagious.”

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Ballmer introduced the Clippers’ new mascot, Chuck the Condor, last month. “I saw the coyote in San Antonio getting the crowd pumped up,” he told me. “That’s what I wanted.”CreditMark J. Terrill/Associated Press

Said Coach Doc Rivers: “He’s brought credibility to this franchise.”

At courtside a few hours before the Clippers-Thunder game, Ballmer explained that he had always been passionate about basketball and had long wanted to buy a basketball team. What held him back, he said, was his “day job.”

In 2008, when Howard Schultz, the Starbucks chief executive and an owner of the Seattle SuperSonics, decided to sell the team, Ballmer joined a group of Seattle businesspeople who tried to buy it. That effort failed, and the Sonics were sold instead to a consortium of Oklahoma City businessmen, who promptly moved it to their hometown.

Five years later, when the Maloof family put the Sacramento Kings on the block, Ballmer wanted to buy the team and move it to Seattle. But David Stern, the N.B.A. commissioner, and Adam Silver, his deputy, told him they wanted an owner who would keep the Kings in Sacramento.

When Ballmer retired in 2014, he became more focused on buying a team. He approached Silver, who had just succeeded Stern, to ask if the league had any expansion plans. No, Silver told him, suggesting that he think instead about buying an existing franchise in a city he was willing to travel to. Ballmer considered Milwaukee but concluded that the two-time-zone commute would be too draining.

It was right about then that TMZ got hold of a taped phone conversation between Sterling and his mistress, V. Stiviano, in which the Clippers owner made a series of deeply offensive racist remarks. Though Sterling didn’t want to sell the team, the pressure to do so was intense, and it came not just from the league and the players, but also from his wife.

Through the auspices of Michael Eisner, the former Disney chief executive and a die-hard Clippers fan, Ballmer got in touch with Shelly Sterling, who was managing the sale. The two hit it off and began negotiating a deal. Ballmer never asked to see the team’s balance sheet — he really didn’t care about that. She was talking to other potential buyers, of course. Although Ballmer had bid well over $1 billion, he told me that he’d heard that someone was going to offer $1.8 billionSo he increased his bid to $2 billion. That sealed the deal.

When I asked Ballmer if he had overpaid for the team, he shrugged. “Things are worth what other people are willing to pay for them,” he replied. “If I could get the deal done at $2 billion, who cares if I overpaid by 5 percent?”

Rivers, whom Sterling had hired the previous summer, had held the team together during the imbroglio, emerging as the hero of the affair. In the vacuum created by the furor over Sterling’s remarks, he had also assumed control of the team’s basketball operations.

Ballmer decided to keep Rivers in that role, naming him president of basketball operations as well as coach — an unusual, though not unprecedented, move. (Think Pat Riley.) Ballmer felt that Rivers had already begun to change the culture of the Clippers and was signing role players who would improve the team.

Rivers also knew how to manage the salary cap, something Ballmer needed to learn. Rivers said that because of the salary cap limits, which Rivers said frustrate Ballmer, “we sign a lot of minimum salaries, and that brings big risks.”

“Sometimes they work out and sometimes they don’t,” he said. “Steve understands that and is willing to take those gambles.”

The culture on the business side has changed as well. I remember visiting the Clippers offices in 2008; it was a dour, unhappy place. On Wednesday afternoon, as I was waiting for Ballmer to arrive, I heard laughter coming from a nearby conference room. Popping my head in, I was introduced to Gillian Zucker, a former auto racing executive whom Ballmer hired to be his president of business operations. Most of the Clippers executive team was sitting around a conference table. Zucker told me that she had just asked everyone to write down three things that people might not know about them. The laughter was the result of trying to figure out who had written what.

As you’d expect of a former Microsoft executive, Ballmer is deeply involved in the Clippers’ digital efforts. (Silver, who put Ballmer on the N.B.A.’s audit committee, told me he often weighs in on the league’s digital business as well.) He hired a director of analytics, hardly a novel move, but a position that Sterling had done without, presumably to save money. And he has dived into things like seat pricing issues. (“Seat pricing is a complex math problem,” Ballmer said. “I like complex math problems.”)

Most of all, he has tried to create a fan base that is as excited about the Clippers as he is. Just last Monday, he introduced a mascot, Chuck the Condor. “I saw the coyote in San Antonio getting the crowd pumped up,” he told me. “That’s what I wanted.” (The early reviews for Chuck the Condor have been, er, mixed.) When the mascot was unveiled during halftime of Monday’s Clippers-Nets game, Ballmer jumped off a trampoline and dunked the ball. It’s impossible to imagine Sterling ever doing something like that.

Of course, the most important thing Ballmer could do to generate enthusiastic fans is put a team on the floor with championship potential. Clippers fans take heart in the fact that the team has played well in their three meetings against the Warriors — but they’ve lost all three games. Hemmed in by salary cap limitations, there is not much more Ballmer can do right now. But next year, the salary cap will rise by an estimated $20 million. If Ballmer can sign a big-time free agent, and with Kobe Bryant retiring from the Lakers, perhaps it won’t be too long before the Clippers are finally able to ascend to the next level — at which point Ballmer will no longer have to worry about fans arriving late.

In the here and now, the Clippers have been playing extremely well, even though Griffin hasn’t played since late December, thanks to an injury. (Griffin also broke his hand in January when he punched — and badly injured — a team trainer. Ballmer and Rivers imposed a four-game suspension, which will take effect once Griffin is healthy again.)

Going into Wednesday’s game, the Clippers’ record was 39-20, and they were jockeying for playoff position with Oklahoma City, which was 42-18. Needless to say, Ballmer was pumped.

The Clippers came out fast, but soon fell behind as Kevin Durant began hitting jumpers and the Thunder kept getting second and third chances. “Let’s go defense!” Ballmer yelled from his seat behind the basket. He stomped his feet angrily after a bad call against Paul.

You could see what the Clippers needed: better defense down low, more aggressive rebounders, and maybe another shooter. By halftime, the Clippers were down by 20 points. Ballmer was discouraged, but like any real fan, he hadn’t lost hope.

The Clippers continued to play poorly into the fourth quarter. But with 7:30 left, down by 16 points, the Clips suddenly came to life — and so did Ballmer. As the Clippers clawed their way back, and Durant lost his touch, Ballmer roared, pumping his fists, and high-fived the friends sitting with him.

When the Clippers took the lead with less than two minutes left, Ballmer lost it completely. Screaming at the top of his lungs, he began joyously slapping the arms and shoulders of his friends. The Jumbotron camera, the one that usually cuts to fans during timeouts, focused on him, so the fans could see the owner cheering his lungs out. When the Clippers emerged with a come-from-behind 103-98 victory, Ballmer raced over to Rivers and they slapped hands. The last I saw him, he was racing out to the locker room.

For that moment, at least, the Clippers’ biggest fan was the happiest man on earth.

Correction:March 6, 2016

Because of an editing error, an earlier version of a picture credit with this article misidentified the photographer. The photograph of Steven A. Ballmer at a Los Angeles Clippers game in October was taken by Jae C. Hong, not Mark J. Terrill.

A version of this article appears in print on , Section D, Page 2 of the New York edition with the headline: Clippers’ Top Fan Is Really Invested in Them (for Billions) . Order Reprints | Today’s Paper | Subscribe